A device based on a novel electrochemical method for the determination of lithium is proposed which can be used in a psychiatrist's office for the analysis of serum or saliva samples. Various electrode designs and experimental techniques will be tested to establish the feasibility of our concept of determining lighium in the presence of the many other components found in serum and saliva. Solutions of various concentrations of LiC1, with NaC1 at concentrations of physiological interest, will be used in preliminary experiments. Next, standard serum and saliva samples will be spiked with LiC1. Finally, clinical samples will be tested, and the results will be compared to a standard laboratory analysis of lithium. Successful development of such a device for monitoring of lithium by a psychiatrist will both improve patient care and decrease medical costs.